Fix error handling if no xml is returned by the XMLHttpRequest
Subscribe to/unsubscribe from threads
Update the subscribe function to use the ApiRequest object
Fix action order for ThreadPage
Reload when going back to the subscriptions page
Subscribe functionality for subforums
Disable subscribing to subscriptions page
Added needed XmlRoles and two related TODO entries
Check whether subscribing to forums is supported in configModel
Push pages via methods in SubForumPage, proper canSubscribe/isSubscribed handling
is_subscribed and can_subscribe implemented for subforums
Do not reload subscriptions page automatically
Allow multiple requests for subscribe actions